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A microcomputer‐controlled data‐acquisition system which is readily adapted to a wide variety of pulsed laser applications is described. Signals are sampled by commercially available gated integrators. Multichannel operation allows data to be normalized to a reference beam intensity, a necessity due to the pulse‐to‐pulse fluctuations of many pulsed lasers. Data are acquired and stored independently for each pulse. The advantages of postacquisition processing versus pulse‐to‐pulse averaging are demonstrated by an example of measurements on a nonlinear system.

Upper‐atmosphere air densities and temperatures have been calculated from the measured trajectory data of a falling sphere. Densities were calculated from the equation for the drag force on the falling sphere, and temperatures were then obtained by using the hydrostatic equation and the equation of state of a perfect gas. The aerodynamic background and instrumentation are described; the method of calculation and the errors are discussed. The results of four rocket flights which carried the experiment are given. Comparison with the average of other rocket measurements indicates agreement with these results.